1. Field of the Invention
The present invention relates generally to the field of hearing aids. The invention further relates to a combination of an adapter and an accessory for a hearing aid.
As used in this context, a hearing aid is understood as generally comprising a device with an input transducer for transforming an acoustic input signal into a first electrical signal, a signal processor for generating a second electrical signal based on the first electrical signal, an output transducer for conversion of the second signal into sound, and a battery for supplying power to the signal processor.
Within the present context, an adapter for a hearing aid designates a device for optional fastening to a hearing aid. The adapter usually serves the purpose of temporarily attaching equipment for use together with the hearing aid, for implementing some specific functionality not incorporated inside the hearing aid, or for providing a connection between the hearing aid and external equipment. The adapter may incorporate means for providing electrical connections to appropriate contact pads of the hearing aid.
An accessory of relevance to the invention comprises a radio receiver such as an FM receiver adapted for receiving an FM radio signal, converting the FM signal into an audio signal and providing the audio signal to the hearing aid, where the audio signal is fed into the hearing aid input circuitry. Other accessories of relevance comprise wireless receivers in general, infrared receivers, connectors for interfacing with other connector systems, audio cables for connection to an external source or another hearing aid, and a programming cable for programming the hearing aid.
2. The Prior Art
DE-30 32 311-A1 discloses a hearing aid with an electronic receiver. The receiver is adapted for receiving FM radio transmissions or infrared transmissions. The receiver attaches to the hearing aid and connects to contacts of the hearing aid. The receiver draws power from the hearing aid battery and supplies a signal to the amplifier.
U.S. Pat. No. 5,734,976 (an equivalent to EP-0 671 818-A1) discloses a micro-receiver for receiving a high frequency, frequency modulated or phase modulated signal adapted for being coupled to a hearing aid.
US Design Pat. D457,635 discloses a hearing aid with a module.
EP-0 806 885-A1 describes a holder for hearing aid accessory components. The holder has a housing open at the front which can be slid over one end of the hearing aid, and devices for removable attachment of the holder on the hearing aid. Electrically conducting leads run on the inside of the housing from the connecting points for the components to the front to make contact with conductors of the hearing aid. The connecting points provide opposing springs that ensure a mechanical and an electrical connection to the accessory component.
EP 0 087 668 A1 provides a hearing aid with a connection holder which is a self-impeding hook, the contacts of which, when hooked onto the case, engage contacts of the aid.
EP 0 334 837 B1 provides a hearing aid with an audio input plug, wherein the audio input connection is made via connecting elements holding together the detachable casing parts.
DE 93 06 204 U1 provides an adapter for a hearing aid, which connects to external pads of the hearing aid and receives a euro-plug.
A commercial implementation of an FM receiver comprises an FM receiver in a miniature cabinet, provided with an integral antenna and a plug. The plug engages a socket in an adapter shoe. The shoe is adapted for clamping onto the housing of a hearing aid. The shoe provides electrical connection to the hearing aid by means of springs adapted for contacting pads on the hearing aid. The user may attach the receiver to the shoe and then the assembly to the hearing aid, or he or she may assemble the parts in the opposite order. Various shoes are manufactured to accommodate different shapes and types of hearing aid housings, all for accommodating a standardized FM receiver.
In this commercial implementation, the receiver plug, referred to as a euro type audio plug, comprises three prongs, arranged in line on the top surface of the receiver housing. The prongs are differentiated in length and in diameter in order to ensure a uniquely defined engagement with the socket. The proper attachment is essential for obtaining the proper electrical connections and for the purpose of obtaining a specific orientation of the integral receiver antenna. The prongs or jacks are held in engagement by springs adapted to resist accidental withdrawal. As the receiver will normally depend from the hearing aid shoe with the prongs oriented vertically, the springs must maintain a firm grip to avoid accidental working loose of the prongs.
Although this design meets all technical requirements, there is a desire for a more convenient solution.
The differentiation among the prongs is not easily perceptible, creating a potential difficulty for a user attempting to identify the proper orientation for assembling the receiver and the adapter.
Pushing the plug into the socket requires a firm grip on the hearing aid for obtaining sufficient engagement, as the force generally must be applied solely by friction, and as the direction of the force required does not lie centrally of the hearing aid. Separating the parts requires a similar firm grip, as there is no face for easy engagement. The nature of these manipulations must be considered in the light of the typical users, who may be elderly people and perhaps people with impaired dexterity.
The socket occupies considerable space inside the adapter. The prongs need a firm structure below the receiver top surface for retention and support. This adds to the length of the composite assembly. The entire assembly has a rather irregular and bulky appearance.